The direct synthesis of wholly aromatic poly(p-phenylene)s bearing sulfobenzoyl side groups as proton exchange membranes

Sulfonated poly(p-phenylene)s (SPPs) containing sulfonic acid groups in their side chains had been directly synthesized by Ni(0) catalytic coupling of sodium 3-(2,5-dichlorobenzoyl)benzenesulfonate and 2,5-dichlorobenzophenone. The synthesized copolymers possessed high molecular weights revealed by their high viscosity, and the formation of tough and flexible membranes by casting from DMAc solution. The copolymers exhibited excellent oxidative stability and mechanical properties due to their fully aromatic structure extending through the backbone and pendent groups. Transmission electron microscopic (TEM) analysis revealed that these side-chain type SPP membranes have a microphase-separated structure composed of hydrophilic side-chain domains and hydrophobic polyphenylene main chain domains. The proton conductivities of copolymer membranes increased with the increase of IEC and temperature, reaching values above 3.4 x 10(-1) S/cm at 120 degrees C, which are almost 2-3 times higher than that of Nafion 117 at the same measurement conditions. Consequently, these materials proved to be promising as proton exchange membranes.

Study on QSPR of alcohols with a novel edge connectivity index F-m

A novel edge degree f(i) for heteroatom and multiple bonds in molecular graph is derived on the basis of the edge degree delta(e(r)). A novel edge connectivity index F-m is introduced. The multiple linear regression by using the edge connectivity index F-m and alcohol-type parameter delta, alcohol-distance parameter L can provide high-quality QSPR models for the normal boiling points (BPs), molar volumes (MVs), molar refraction (MRs), water solubility(log(1/S)) and octanol/water partition (logP) of alcohols with up to 17 non-hydrogen atoms. The results imply that these physical properties may be expressed as a liner combination of the edge connectivity index and alcohol-type parameter, 6, alcohol-distance parameter, L. For the models of the five properties, the correlation coefficient r and the standard errors are 0.9969,3.022; 0.9993, 1.504; 0.9992, 0.446; 0.9924,0.129 and 0.9973,0.123 for BPs, MVs, MRs, log(1/S) and logP, respectively. The cross-validation by using the leave-one-out method demonstrates the models to be highly reliable from the point of view of statistics.

Synthesis and characterization of hyperbranched aromatic poly(ether imide)s

The four AB(2) monomers, N-[3- or 4-bis(4-hydroxyphenyl)toluoyl]-4-chlorophthalimide and N-{3- or 4-[1,1-bis(4-hydroxyphenyl)]ethylphenyl}-4-chlorophthalimides, were prepared and used for synthesis of hyperbranched poly(ether imide)s bearing hydroxyl end groups. These hyperbranched poly(ether imide)s had moderate molecular weights with broad distributions and showed glass-transition temperatures (Tgs) between 177 and 230 degreesC. The thermogravimetric analytic measurement revealed the decomposition temperature at 5% weight-loss temperatures (T-d(5%)) ranging from 240 to 281 degreesC. Analysis using H-1 NMR spectroscopy revealed the four types of hyperbranched poly(ether imide)s to have similar degrees of branching (ca. 60%). These polymers were modified by acylation or nucleophilic substitution reaction at the hydroxyl end groups. The conversion effectiveness depended on the type of modification reaction, modifier, and reaction conditions. The thermal stability and solubility of hyperbranched poly(ether imide)s were improved by the modification of the end groups.

Synthesis and characterization of hyperbranched aromatic poly(ester-imide)s

The synthesis and characterization of hyperbranched aromatic poly(ester-imide)s are described. A variety of AB(2) monomers, N-[3- or 4-bis(4-acetoxyphenyl)toluoyl]-4-carboxyl-phthalimide and N-{3- or 4-[1,1-bis(4-acetooxyphenyl)]ethylphenyl}-4-carboxy phthalimides were prepared starting from condensation of nitrobenzaldehydes or nitroacetophenones with phenol and used for synthesis of hyperbranched poly(ester-imide)s containing terminal acetyl groups by transesterification reaction. These hyperbranched poly(ester-imide)s were produced with weight-average molecular weight of up to 6.87 g/mol. Analysis of H-1 NMR and C-13 NMR spectroscopy revealed the structure of the four hyperbranched poly(ester-imide)s. These hyperbranched poly(ester-imide)s exhibited excellent solubility in a variety of solvents such as N,N-dimethylacetamide, dimethyl sulfoxide, and tetrahydrofuran and showed glass-transition temperatures between 217 and 255 degreesC. The thermogravimetric analytic measurement revealed the decomposition temperature at 10% weight-loss temperature (T-d(10)) ranging from 365 to 416 degreesC in nitrogen.

Preparation, photo and electroluminescence properties of novel rare earth aromatic carboxylates

Novel soluble rare earth aromatic carboxylates were prepared. The triplet energy level of organic ligand was measured. The photoluminescence properties of the Tb3+ and EU3+ aromatic carboxylates and lifetimes were investigated, which indicated that these rare earth complexes have high quantum efficiency. Because of their excellent solubility, polymer-doping rare earth carboxylates were fabricated as thin Films by spin-coating method and their luminescence properties were studied. Some rare earth organic light-emitting diodes were successfully fabricated which performed high pure color. The maximum luminance of the device of ITO/PVK/PVK :Th (AS)(3)Phen: PBD/PBD/Al is 32 cd(.)m(-2) at 28 V.

Synthesis of aromatic diaminospirodilactone

A new kind of aromatic diaminospirodilactone, i.e. 6,6'-diamino-3, 3'-spirobiphthalide, was synthesized through multistep reactions from p-nitrotoulene and paraformaldehyde, It was: found that dinitrospirolactone could be synthesized directly in the acid system through oxidation reaction with a high yield, The increase of solvent polarity leads to an increase of reduction yield of dinitrolactone. The resulting intermediates 6, 6'-dihydroxylamino-3, 3'-spirobiphthalide and 6-amino-6'-hydroxylanimo-3, 3'-spirobiphthalide were steady aromatic hydroxylamine. The structures of 6, 6'-diamino-3, 3'-spirobiphthalide and its intermediates were confirmed by H-1 NMR, C-13 NMR, MS, IR and elemental analyses.

Aromatic poly(ester imide)s and poly(amide imide)s having 1,1 '-binaphthyl-2,2 '-diyls in the main chain

Full Paper: Two new 1,1'-binaphthyl-2,2'-diyl-based dianhydrides, i.e., 2,2'-bis(3,4-dicarboxybenzamido)-1,1'-binaphthyl dianhydride (BNDADA) and 2,2'-bis(3,4-dicarboxybenzoyloxy)-1,1'-binaphthyl dianhydride (BNDEDA), were synthesized and polymerized with various aromatic diamines to afford polyimides through the traditional two-step method. The polyimides with inherent viscosities ranging from 0.27 to 0.70 dl . g(-1) showed excellent solubilities in polar solvents such as DMAc, DMSO and NMP etc., except of the poly(ester imide) prepared from BNDEDA and benzidine. Poly(ester imide)s based on BNDEDA can also be readily dissolved in weakly polar solvents such as THF, CH2Cl2 and CHCl3. The glass transition temperatures of these polyimides are in the range of 210-310 degrees C; the 5% weight loss temperatures are in the range of 390-465 degrees C in nitrogen and 384-447 degrees c in air. These polymers from light yellow, tough films that were transparent above 365 nm. The effects of different flexible units attached in the 2- and 2'-positions, i.e., amide, ester and ether, on the properties of the polyimides obtained are discussed.

Advances in gas-phase electrophilic aromatic substitution reaction

Recent advances in the gas - phase reaction of aromatics with cationic electrophiles are reviewed. The overall substitution reaction is analyzed in terms of its elementary steps. Mechanistic studies have been focused on the structure and reactivity of covalent and non - covalent ionic intermediates, which display a rich chemistry and provide benchmark reactivity models. Particular attention has been devoted to proton transfer reactions, which may occur intra or intermolecularly in arenium intermediates.

Synthesis and characterization of aromatic dianhydrides and polyesterimides derived from 4-hydroxyphthalic anhydride

4-Hydroxyphthalic anhydride, prepared from 4-chlorophthalic anhydride, was reacted with trimellitic anhydride monoacid chloride or arylene diacid chloride to give aromatic ester-containing dianhydrides (EDAs). These dianhydrides were characterized by element analysis, melt point, FTIR and H-1-NMR. A series of aromatic poly (amic ester acid)s was synthesized by polycondensation of these EDAs and various diamines in polar organic solvent. The inherent viscosity of poly (amic ester acid)s ranged from 0.55 to 0.89 dL/g, indicating the intermediate to higher molecular weight. Polyesterimides having glass transition temperatures between 184-219degreesC were produced by thermal imidization of corresponding poly (amic ester acid)s. These polymers were fairly resistant to organic solvent, but some of them were soluble in phenol solvents. Thermogravimetric analyses revealed that these polyesterimides were stable up to 400degreesC, and the 5% weight loss temperatures were recorded in the range of 432-483degreesC in air atmosphers and 451-490degreesC in nitrogen.

Synthesis and characterization of optically active aromatic polyimides derived from 2,2 '-bis(2-trifluoro-4-aminophenoxy)-1,1 '-binaphthyl and aromatic tetracarboxylic dianhydrides

Optically active 2,2'-bis(2-trifluoro-4-aminophenoxy)-1,1'-binaphthyl and its corresponding racemate were prepared by a nucleophilic substitution reaction of 1,1'-bi-2-naphthol with 2-chloro-5-nitrotrifluorotoluene and subsequently by the reduction of the resulting dinitro compounds. a series of optically active and optically inactive aromatic polyimides also were prepared therefrom, These polymers readily were soluble in common organic solvents such as pyridine, N,N'-dimethylacetamide, and m-cresol and had glass-transition temperatures of 256 similar to 278 degrees C. The specific rotations of the chiral polymers ranged from 167 similar to 258 degrees, and their chiroptical properties also were studied. (C) 1999 John Wiley & Sons Inc.

Gas-phase ion - Molecule reactions of neutral C-60 with the plasmas of alkyl methyl ethers and primary alcohols

The gas-phase ion-molecule reactions of C-60 with the methoxymethyl ion [CH3O=CH2](+) and the 1-hydroxyethyl ion [CH3CH=OH](+) generated under the self-chemical-ionization (self-CI) conditions of alkyl methyl ethers and primary alcohols were studied in the ion source of a mass spectrometer. The adduct ions [C60C2H5O](+) and protonated molecules [C60H](+) were observed as the major products of C-60 with the plasma of alkyl methyl ethers. On the contrary, the reactions of C-60 With the plasmas of primary alcohols produced few corresponding adduct ions. The AM1 semiempirical molecular orbital calculations were carried out on 14 possible structures. The calculated results showed that the most stable structure among the possible isomers of [C60C2H5O](+) is the [3+2] cycloadduct. According to experimental and theoretical results, the pathway for the formation of the adduct was presented.